This invention relates to vibratory devices, such as a vibrating conveyor, vibrating feeder and the like, and, more particularly, to such devices wherein it is desirable to adjust the frequency and/or the stroke of the drive means for the vibratory device.
Heretofore, various means have been provided for adjusting the frequency and/or the stroke of the drive means for such vibratory devices. Prior to the advent of my U.S. Pat. No. 3,251,457 (the basic structure and operation of which is shown in FIGS. 1 and 1A of the present drawing), most of these frequency and stroke adjusting means had been mechanical rather than electrical. The disclosure to the public of these previously patented electrical means of mine and their simplicity and greatly reduced costs when compared to the old mechanical forms has since led to their present general usage by the vibratory device industry.
However, in follow up to my development of this previously patented structure of mine, I have now found that, in accordance with the present invention, satisfactory and yet less expensive electrical means can be provided for adjusting the frequency and stroke of such vibratory devices. These latest means of mine (illustrated in FIGS. 2 and 2A of the present drawing permit approximately yet another one-third reduction in costs over those described in my aforenoted earlier patent.